JPS60124149A - Four/six bit modulating method - Google Patents

Four/six bit modulating method

Info

Publication number
JPS60124149A
JPS60124149A JP23240183A JP23240183A JPS60124149A JP S60124149 A JPS60124149 A JP S60124149A JP 23240183 A JP23240183 A JP 23240183A JP 23240183 A JP23240183 A JP 23240183A JP S60124149 A JPS60124149 A JP S60124149A
Authority
JP
Japan
Prior art keywords
bit
inversion interval
code
codes
bits
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP23240183A
Other languages
Japanese (ja)
Inventor
Yoriyasu Takeguchi
竹口 順康
Takanori Senoo
孝憲 妹尾
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Priority to JP23240183A priority Critical patent/JPS60124149A/en
Publication of JPS60124149A publication Critical patent/JPS60124149A/en
Pending legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10Digital recording or reproducing
    • G11B20/14Digital recording or reproducing using self-clocking codes
    • G11B20/1403Digital recording or reproducing using self-clocking codes characterised by the use of two levels
    • G11B20/1423Code representation depending on subsequent bits, e.g. delay modulation, double density code, Miller code
    • G11B20/1426Code representation depending on subsequent bits, e.g. delay modulation, double density code, Miller code conversion to or from block codes or representations thereof

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)
  • Dc Digital Transmission (AREA)
  • Signal Processing For Digital Recording And Reproducing (AREA)

Abstract

PURPOSE:To set up a DC component to ''0'', to increase the width of a detecting window and the minimum inversion interval and to reduce the maximum inversion interval by replacing 4-bit data in a binary data string divided in each 4 bits by a 6-bit code and NRZI-modulating the 6-bit code. CONSTITUTION:An input data string is divided in each 4 bits and converted into 6-bit codes in accordance with a conversion table shown in table (I) by a 4/6 bit conversion part 3 and the 6-bit codes are modulated and outputted by/from an NRZI conversion part 2. The 6-bit code is selected when the difference between the ''high'' period and ''low'' period of a signal of the code itself is ''0'', i.e. the total digital value is ''0''. The sum of codes setting the minimum inversion interval to 2T/3 and the maximum inversion interval to 2T is 18 codes. These code words are satisfied with the conditions of the minimum inversion interval and the maximum inversion interval even at the connection parts of the code words. A data word consisting of 4 bits requires 16<= more code words.

Description

【発明の詳細な説明】 産業上の利用分野 本発明は、ディジタル信号の伝送又は記録再生に用いる
ことのできる4−6変調方法に関するものである。
DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a 4-6 modulation method that can be used for transmitting, recording and reproducing digital signals.

従来例の構成とその問題点 近年、ディジタル信号を光ティスフや磁気ティスフテー
プ等々記録再生する際に1記録再生をより安定に行なう
目的で、各種の変調方式が用いられている。以下図面を
参照しながら従来の代表的な変調方法である4−5変調
方法について説明する。第1図は従来の4−5変調方法
のブロック図を示し、(1)は4−6父侠都・(2)は
N凡ZI度換部であるe第1表は、4−5i換部(1ン
で4ビツトデータを5ビット9〕−号に変換すなための
変換表である。
Conventional Structures and Their Problems In recent years, various modulation methods have been used for the purpose of more stably recording and reproducing one recording/reproduction when recording and reproducing digital signals on optical or magnetic TiSF tapes. The 4-5 modulation method, which is a typical conventional modulation method, will be described below with reference to the drawings. Figure 1 shows a block diagram of the conventional 4-5 modulation method. This is a conversion table for converting 4-bit data into 5-bit 9-bit data in one line.

以上の様に構成された4−5’&J1.′、1方法につ
いて以下に説す」する0人力2進テータ列は4−5変換
部(1)で4ビツト毎に分割式れ、各々の4ビツトの値
に従って第1表に示す変換表に基ついて各々5ヒツト符
号に置換され1さらにNILZI変侠部(2)で、4−
5変換後のビット列中で1のビットのある場所で出力イ
ラ号を反転させ、0のビットでは直前の信号レベル全そ
のまま維持する、いわゆるNRZI変調を行なった後に
出力していた。しかしながら、上記の様な変換規則では
、変調後の信号のノ・イの第1表 期間の和とローの期間の和との差であるところの直流成
分が0とはならず、直流成分を通さない伝送1記録媒体
を用いた場合、再生が非常に困難になるという問題点を
有していた・例えば亀回転トランスを通して結合される
回転ヘッドによる配録再生系は、回転トランスが交流結
合素子であるため、直流成分を持つ記録電流波形は歪〆
しでしまう。
4-5'&J1. configured as above. ', 1 method will be explained below.' The 0-manual binary data string is divided into 4-bit units in the 4-5 converter (1) and converted into the conversion table shown in Table 1 according to the value of each 4-bit. Each of the bases is replaced with a 5-hit code, 1, and in the NILZI variable part (2), 4-
5. In the bit string after conversion, the output error signal is inverted at a location where there is a 1 bit, and at a 0 bit, the previous signal level is maintained as it is, so-called NRZI modulation is performed and then output. However, with the above conversion rule, the DC component, which is the difference between the sum of the No and No Table 1 periods of the modulated signal and the sum of the low periods, does not become 0; If a recording medium that does not pass through the transmission 1 is used, reproduction becomes extremely difficult.For example, in a recording/reproduction system using a rotating head coupled through a tortoise rotary transformer, the rotary transformer is an AC coupling element. Therefore, the recording current waveform having a DC component is distorted.

上記の様な問題点を解決するため、ZM(Zer。In order to solve the above problems, ZM (Zer.

Modulation )と呼ばれる変調方法が従来例
としである。これは1ビツトLデ一タ語を2ビツトの符
号語に変換して、さらに直流成分がOになる様に工夫さ
れた変調方法である。
A conventional modulation method is called "Modulation". This is a modulation method devised to convert a 1-bit L data word into a 2-bit code word so that the DC component becomes O.

しかしながら、上記の変調方法では、変調前のデータの
1ビツト長(ITとする)に対して1検出窓幅1)i 
Q、5T’になってしまうため、高密度記録再生を行な
う時、検出窓のマージンが少なく1再生が困難になって
しまうという問題点を有していた。
However, in the above modulation method, 1 detection window width 1) i
Q, 5T', there is a problem that when performing high-density recording and reproduction, the margin of the detection window is small, making it difficult to perform one reproduction.

発明の目的 本発明の目的は、直流成分が完全にOになることを可能
にし、かつ検出窓幅、最小反転間隔をできるだけ大きく
、最大反転間隔をできるだけ小さくかつハードウェアが
簡単になる変調方法を提供することである。
OBJECTS OF THE INVENTION An object of the present invention is to provide a modulation method that allows the direct current component to become completely O, increases the detection window width and minimum inversion interval as much as possible, minimizes the maximum inversion interval as much as possible, and makes the hardware simple. It is to provide.

発明の構成 上記目的を達成するために、本発明は2進データ列を4
ビツト毎に分割し、各々の4ビツトデータを、七の値に
応じて対応する6ビツトの符号で置き換え、その符号列
をNRZI変調する様に構成したものであり、これによ
り直流成分が完全に0になり、検出窓幅、最小反転間隔
を大きく1最大反転間隔を小さくすることができるもの
である。
Structure of the Invention In order to achieve the above object, the present invention converts a binary data string into four
The data is divided into bits, each 4-bit data is replaced with a corresponding 6-bit code according to the value of 7, and the code string is NRZI modulated. This completely removes the DC component. 0, the detection window width and the minimum reversal interval can be increased, and the maximum reversal interval can be decreased.

実施例の説明 以下本発明の一実施例について、図面を参照しながら説
明をする。第2図は本発明の一実施例における4−6変
調方法のブロック図を示すものである。第2図において
、(a)rJ: 4− a変換部1(2)はNILZI
変換部である。又、第2表は4−6変換部(3)におい
て、人力4ピツトテータを6ビツトの符号に変換するた
めの変換表である・ 以上の様に構成された本実施例の4−6変換方法につい
て以下に説明する。まず入カテータ列は4−6変換部(
3)で4ビツト毎に分割され、第2表の変換表に従って
6ビツトの符号に変換され、NRZI変換部(2)で、
NRZI変調が行なわれて出力される。
DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows a block diagram of a 4-6 modulation method in one embodiment of the present invention. In FIG. 2, (a) rJ: 4-a converter 1 (2) is NILZI
This is the conversion section. Table 2 is a conversion table for converting the manual 4-bit data into a 6-bit code in the 4-6 converter (3). The 4-6 conversion method of this embodiment configured as described above. will be explained below. First, the input categorization unit is the 4-6 converter (
3), it is divided into 4 bits, converted into a 6-bit code according to the conversion table in Table 2, and then converted into a 6-bit code in the NRZI conversion section (2).
NRZI modulation is performed and output.

第2表の6ビツト符号の選定は以下の様に行なう、6ビ
ツト符号自身で)イら号のハイの期間とローの期間の差
が01すなわちテイジタル総和値(以下D8■と略す)
が0になっており、しかも最小反転間隔が”/B s最
大反転間隔が8T/8となる符号の総数は18個ある。
The 6-bit code in Table 2 is selected as follows.The difference between the high period and low period of the 6-bit code itself is 01, that is, the digital sum value (hereinafter abbreviated as D8).
is 0, and the minimum inversion interval is "/Bs. The total number of codes in which the maximum inversion interval is 8T/8 is 18.

これらの符号語は符号語の接続部においても最小反転間
隔と最大反転間隔の条件を満足している。データ語のビ
ット数は4ビツトであるので1条件を満す符号語の数は
16イ一以上あれば良い。したがって11Nl+!++
の符号語の中から16個選択する。内生時、信号からセ
ルフクロックを生成するため、信号の反転間隔は小さい
程、有利である。そのため最大反転間隔8′/8が発生
しないものから優先的に選択する。反転間隔が最大2T
となる符号語の数は15iあるので、これらをすべて第
2表 使用する。残りの1個は”001001’ 、 ”00
1011 ” 、 ”001110“08個の中から選
択しなけれはならない・本実施例では1反転回数の多い
符号語を選択するという観点から“001011“ を
使用した。第2表ではデータ語の”0110”がこれに
相当する。
These codewords also satisfy the minimum inversion interval and maximum inversion interval conditions at the codeword connection. Since the number of bits of a data word is 4 bits, the number of code words satisfying one condition may be 16 bits or more. Therefore 11Nl+! ++
Select 16 code words from among the code words. Since a self-clock is generated from a signal during endogeneity, the smaller the signal inversion interval, the more advantageous it is. Therefore, those in which the maximum inversion interval of 8'/8 does not occur are selected preferentially. Maximum reversal interval is 2T
Since there are 15i code words, all of them are used in Table 2. The remaining one is “001001”, “00”
1011'', ``001110'' must be selected from among the 08 codes. In this embodiment, ``001011'' is used from the viewpoint of selecting a code word with a large number of 1 inversions. In Table 2, the data word ``0110'' ” corresponds to this.

発明の効果 以上の説明から明らかな様に、本発明は人力2進データ
タ1jを4ビツト毎に分割し、各ビットデータを、その
値に応じて対応する6ビツト符号に変換してflH4Z
I変調を行なっているので、直流成分を0にてき1かつ
検出窓幅、最小反転間隔を大きく、最大反転間隔を小さ
くすることができ、記録、伝送の^密度化が可能になる
という優れた効果が得られる。特に伝送系に父流鯖合累
子を用いている場合は、直流成分が0であるという効果
が再生波形のノイズマージンを大きくするという効果を
もたらす。
Effects of the Invention As is clear from the above explanation, the present invention divides the human-powered binary data data 1j into 4 bits, converts each bit data into a corresponding 6-bit code according to its value, and converts it into flH4Z.
Since I modulation is performed, the DC component can be reduced from 0 to 1, and the detection window width, minimum inversion interval can be increased, and maximum inversion interval can be decreased, making it possible to increase the density of recording and transmission. Effects can be obtained. Particularly when the transmission system uses a transmission system using a transmission system, the effect that the DC component is 0 has the effect of increasing the noise margin of the reproduced waveform.

また、本発明は1デ一タ語に対して1符号語を対応させ
ているので、lデータ語に対して複数の符号語を対応さ
せたり1例外規則のある変調方法と比較して、ハードウ
ェアが簡単になると(1う優れた効果がある。
In addition, since the present invention associates one code word with one data word, it is difficult to use the hard When the clothes become easier (1) there are better effects.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は従来の4−5変調方法のブロック図、第2図は
本発明の一実施例における4−6変調方法のブロック図
である− <2)−pifLzx yp部、 (3)−4−6Km
部代理人 森本義弘 第1図
FIG. 1 is a block diagram of a conventional 4-5 modulation method, and FIG. 2 is a block diagram of a 4-6 modulation method in an embodiment of the present invention. -6Km
Department agent Yoshihiro Morimoto Figure 1

Claims (1)

【特許請求の範囲】[Claims] 1.2進データ列を4ビツト毎に分割1ノ1各々の4ビ
ツトデータを、その値に応じて対応する6ビツトの符号
で置き換え・その符号列をNRZI変調する4−6父v
ra方法02.6ビツト符号は、それ自身の直流成分が
0のものを割り当てることを特徴とする特許請求の範囲
第1項記載の4−6変調方法03.6ビツト符号は、最
小反転間隔が /8)最大反転間隔か 4となる様に選
定しであることを特徴とする特許請求の範囲第1項又は
第2項記載の4−6変調方法e
1. Divide the binary data string into 4-bit units Replace each 4-bit data with the corresponding 6-bit code according to its value and modulate the code string with NRZI 4-6 father v
The 4-6 modulation method 03.6-bit code according to claim 1 is characterized in that the ra method 02.6-bit code is assigned its own DC component of 0. /8) The 4-6 modulation method e according to claim 1 or 2, characterized in that the maximum inversion interval is selected to be 4.
JP23240183A 1983-12-08 1983-12-08 Four/six bit modulating method Pending JPS60124149A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP23240183A JPS60124149A (en) 1983-12-08 1983-12-08 Four/six bit modulating method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP23240183A JPS60124149A (en) 1983-12-08 1983-12-08 Four/six bit modulating method

Publications (1)

Publication Number Publication Date
JPS60124149A true JPS60124149A (en) 1985-07-03

Family

ID=16938660

Family Applications (1)

Application Number Title Priority Date Filing Date
JP23240183A Pending JPS60124149A (en) 1983-12-08 1983-12-08 Four/six bit modulating method

Country Status (1)

Country Link
JP (1) JPS60124149A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03145334A (en) * 1989-10-31 1991-06-20 Sony Corp Digital modulating method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03145334A (en) * 1989-10-31 1991-06-20 Sony Corp Digital modulating method

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